234 PROCEEDINGS OF THE AMERICAN ACADEMY. 



I. 0.2384 gram of the substance gave 25.1 cc. of nitrogen at a temper- 

 ature of 2o° and a pressure of 753.3 nun. 

 II. 0.2887 g • tm of the substana by the method of C'arius 0.2910 



gram of argentic bromide. 



Found. 



II. 



12.89 



The substance is, therefore, dibromtrinitrobenzol ( Br s l. 3.1 N( > ,2. I. 6 I, 

 formed by the replacement of one atom of bromine in the tribromtrini- 

 trobenzol by hydrogen, and the Bodic sulphite bas behaved like a reduc- 

 ing agent in this case just as it did with the tribromdinitrobenzol. 



Properties of Metadibrom-s-trinitrobenzol. — It crystallizes from ben- 

 zol -or better, a mixture of benzol and ligroin — in broad prisms termi- 

 nated by two planes at a slightly acute angle to each other, or in slender, 

 blunt-ended prisms, or in rhombic crystals. It has a pale yellow color with 

 a slight greenish tinge, and melts al 135°. It is freely Boluble in benzol 

 or ether; soluble in chloroform, acetone, or cold alcohol, freely soluble 

 in hot alcohol ; slightly Boluble in hoi ligroin; insoluble in water. The 

 best solvent for it is a mixture of alcohol and benzol, or of benzol and 

 ligroin ; strong hydrochloric or Bulphuric acid has no action on it. either 

 hot or cold. Strong nitric acid due-, not dissolve it in the cold, hut 

 form- a yellow solution with it when hot, which deposits the unaltered 

 substance on cooling. Sodic hydrate solution gives a pale yellow solu- 

 tion when hot: no perceptible action when cold. Alcoholic sodic 

 hydrate gives a deep red color. 



The aqueous wash waters obtained in the preparation of dibromtri- 

 nitrobenzol by this process, although showing a Btrong red color, con- 

 tained so little organic matter that we did not Bucceed in isolating any 

 new compound from them. The residue left mi evaporating them 

 consi-:rd chiefly of Bodic bromide and unaltered sodic Bulphite. 



Preparation of Dibromtrinitrobenzol from Dibromdinitrobenzol, 



In the hope of finding an easier method of preparing the dibromtrini- 

 trobenzol we next tried to make it from dibromdinitrobenzol. The 

 dibromdinitrobenzol was mad'- by the method of Jackson and Cohoe, * 

 which, however, we modified Bomewhat in converting the bromacetanilid 



* These Proce< dUi _■-. \\\vi. 77. 



